Oscillator control system



H. W. LENSNER OSCILLATOR CONTROL SYSTEM July 18, 1950 2,516,007

Filed April 8, 1944 Patented July 18, 1950 2,516,007 OSCILLATOR CONTROL SYSTEM Herbert W. Lensner, East Orange, N. J.,

to Westinghouse Electric assigner Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application April 18, 1944, Serial No. 530,134

(Cl. Z50-36) 4 Claims. l

My invention relates to dual-purpose carriercurrent systems, which are associated with electric transmission lines for aiding in the protective relay control for tripping the line-sectionalizing circuit-interrupting means in the event or" a line-fault, and which are also commonly utilized for telemetering and other purposes. The combined use of telemetering and faultresponsive relay-controls, in the circuits previously utilized, has entailed complications involving extra relays for segregating and interlocking the different kinds of control, and it has also entailed an almost prohibitive burden on the telemetering contacts when utilized with the present-day high-rate telemetering system which calls upon the contacts to start and stop carriercurrent transmission from 40 to 200 times a minute. These telemetering contacts have had to make and break anywhere from 0.4 to 0.9 ampere at 125 volts direct-current, and under such severe service their life was very short.

The principal object of the present invention is to provide an electronic keyer which is utilized for controlling the carrier-current transmission. rlhis keyer preferably comprises a lowpowered oscillator, and the telemetering contacts are preferably placed in the grid-circuit of this oscillator, where the power is only a few milliwatts. This arrangement thus completely solves the problem of sparking telemetering contacts. The fault-responsive relay-control contacts may either be applied to the electronic keyer, or to the carrier-current transmitter, and in any event they are preferably placed in a diierent circuit than the telemetering contacts. so that the relaying operations can be more conveniently segregated without introducing complications in the circuits.

With the foregoing and other objects in view, my invention consists in the circuits, systems, combinations, parts, and methods hereinafter described and claimed, and illustrated in the accompanying drawing, in which:

Figure 1 is a diagrammatic view of circuits and apparatus embodying my invention in a preierred form of embodiment, and

Fig. 2 is a schematic diagram of the directcurrent connections of a modified embodiment of that portion of the invention which is shown below the line II-II in Fig. l.

My invention is illustrated in connection with a three-phase line 3 which is connected to a three-phase bus i through a three-pole circuitbreaker 5 which is provided with an auxiliary vmake-contact switch 5a, and a trip-coil TC.

`one for ground-fault responses.

The illustrated system utilizes line-conditionresponsive relays, the alternating-current connections of which are shown in the upper leithand portion of Fig. l, and also direct-current relaying connections which are shown in the right-hand portion of Fig. l. The relays are arranged in four panels il, i2, it, and i4; one for each of the three phases, and the fourth Relaying energy is supplied by means of line-current transformers l5, auxiliary current-transformers I6, bus-connected potential-transformers il, and auxiliary potential-transformers i8, in a manner which is now more or less common and well known, and which, therefore, needs no detailed explanation.

The relays for the three line-phases A, B, and C are distinguished by the letters A, B, and C in the several relay-designations, and only the phase-A relays are indicated in detail. As shown in the panel il, these phase-A relays comprise a directional element DA, having a current-coil DA and a voltage-coil DAV; and also iirst, second, and third-zone distance-responsive elements ZIA, ZZA, and ZSA, having current-energized operating coils ZlA, 22A, and Z3A, respectively, and voltage-energized restraint-windings which are all grouped together under the designation ZAv. rlhe various contacts of the relays are given the same designation as the operating coils or current-responsive coils of the relays themselves, so that the contacts are suiciently identied by reference to the relay-designations such as DA, ZIA, 22A, and 233A.

The ground-fault relays in the panel I4 are shown as comprising a directional element D0 having a voltage-coil DOV, and two residualcurrent overcurrent elements 102 and 103, of which the element 103 is the more sensitive.

l'he illustrated relaying system of Fig. l is associated with the receiver-relay RR of carriercurrentequipment which will be subsequently described. The receiver-relay RR is provided with an operating-coil RR, a restraint-coil RRH, and two sets of contacts which are also designated RR.

Fig. l shows simpliiied tripping circuits for energizing the trip-coil TC ci the circuit-breaker 5, including only those features which contribute to an understanding of my present invention, omitting more or less conventional or optional additions such as back-up protection, out-ofstep protection, and the like. Two tripping circuits are shown for each of the three line-phases A, B, and C.. The phase-A trip-circuit connections extend from the negative bus through the directional contact DA to a conductor 2|, and thence through the rst-zone distanceresponsive contact Z IA to a tripping-bus 22, from which the tripping circuit is completed through the trip-coil TC and the auxiliary breaker-switch a to the positive bus The second phase- A tripping-circuit extends from the conductor 2| through the second-zone distance-responsive contact ZZA to a conductor 23 which is common t0 all three phases of the trip-circuit connections. The phase-B and phase-C tripping cir- .cuits are similar to the phase-A circuits, being distinguished by the distinguishing letters B and C, respectively, and need not be specifically described. The common phase-fault circuitconnection 23 is connected to the tripping-bus 22 through a contact 24 of the receiver-relay RR. This common circuit 23 is also utilized to energize an auxiliary, directionally responsive, phasefault relay or contactor-switch CSP.

The ground-fault tripping-circuit which is illustrated in Fig. 1 comprises a circuit which extends from the negative bus through the directional contact DO and overcurrent contact IO2, to a conductor 25, and thence through a receiver-relay contact 26 to the tripping-bus 22. The conductor 25 is also utilized to energize an auxiliary, directicnally responsive, ground-fault relay or contactor-switch CSG.

In the form of my invention which is shown in Fig. 1, the contacts of the three third-zone distance-elements Z3A, Z3B and Z3C are connected together in parallel between the negative bus and a common circuit-connection 21. This common connection 21 is utilized to energize an auxiliary keyer-controlling relay or contactor-switch CSK, which will be subsequently referred to. From the common circuit-connection 21, a carrier-current control-circuit continues through the back-contact CSP of the auxiliary phasefault relay CSP, to a conductor 28, and thence through the back-contact CSG of` the auxiliary ground-fault relay CSG, to a conductor 29. The conductor 28 is also connected to the negative bus through the contact IO3 of the sensitive ground-fault overcurrent relay IO3, in such manner as to provide ground-preference in a known way. The two serially-connected backcontacts CSP and CSG are shunted by a circuit containing the` receiver-relay operating-coil RR and a resistance RI.

The carrier-current control-circuit, up to the point 29, is the standard, so-calledA cathode-circuit control, which is shown and claimed in a patent of Lenehan andv Goldsborough, No. 2,255,934, granted September V16, 194'1, and assigned to the Westinghouse Electric & Manufacturing Company. As shown in this patent, this cathode-circuit control is utilized in the cathodelead of the transmitterv oscillator-tube of the carrier-current transmitter. `In my present invention, I utilize this same circuit-control connection in the plate-circuit of an auxiliary oscillator-tube OSC, which is utilized as an electronic keyer for controlling the carrier-current transmitter in a manner which will be subsequently described.

As shown in Fig. 1, the keyer-oscillator OSC is I provided with a plate-circuit which extends from the positive bus (-1-) through a series droppingresistor R2 to the conductor 29, and thence through a radio-frequency choke RFC to the anode-lead 3| of the keyer-oscillator OSC. The cathode-lead 32 of this oscillator is connected to a suitable negative source, such as the negative bus as shown.

The keyer-oscillator OSC is connected to a tuned circuit comprising two capacitors CI and C2, and the primary winding of a transformer 33. The cathode-lead 32 is connected to the intermediate point between the two capacitors C! and C2. The junction point between the capacitor C| and the transformer-primary 33 is connected to the grid-terminal 34 of the keyer-oscillator OSC. The grid-terminal 34 is also connected to the cathode-lead 32 through a grid-leak GL. The junction-point 35 between the capacitor C2 and the transformer-primary 33 is connected, through a blocking-capacitor BCI, to the anodelead 3| of the keyer-oscillator OSC. The keyeroscillator OSC, as thus described, is normally continuous by operating. Its operation can be discontinued, through the relay-responsive control-circuits, by bringing the potential of the point 29 down substantially to the potential of the negative bus or to such a low value that the potential-difference between this point 29 and the cathode-lead 32 is insuiiicient to maintain tubeoscillation. The operation of the tube may be restored, by again raising the potential of the point 29 to a value which is suinciently positive, with respect to the cathode-lead 32, to produce oscillations, as by the opening of the back-contact CSP or CSG.

In accordance with one feature of my present invention, I connect the telemetering contact, which is indicated at TM, in or to the gridcircuit 34 of the keyer-oscillator, in such manner as to block the oscillations of the oscillator when the telemetering contact TM is closed. I have shown the telemetering contact TM in a circuit which short-circuits the grid-leak GL of the keyer-oscillator tube OSC. This grid-leak short-circuiting circuit may be traced from the negative bus through the normally open telemetering key-contact TM, anda back-contact CSK of the auxiliary keyer-controlling relay CSK, to the grid-terminal 34 of the keyeroscillator OSC.

In this manner, when the telemetering key TM is closed, under normal operating conditions when there is no fault on the transmission system, the grid-leak GL of the keyer-oscillator OSC is short-circuited, thereby blocking the generation of oscillations by the oscillators. The CSK contact is utilized as a convenient fault-responsive means for preventing the telemetering key TM from blocking the keyer-oscillations at a time when the relaying requirements may call for an oscillating condition of the keyer-oscillator OSC. Thus, when either one of the phasefault or ground-fault auxiliary switches CSP or CSG picks up, the back-contacts of these switches restore a positive potential to the point 29 which should guarantee an oscillating condition of the keyer-oscillator OSC, in order to obtain correct protective-relay operation. The auxiliary keyercontrolling relay CSK is provided as a convenient means for making sure that the telemetering key TM has no control over the oscillation of the keyer-oscillatorOSC, at any time when there is a fault on the transmission system, and when the fault-responsive protective relaying equipment may require an operative or oscillating condition of the keyer-oscillator OSC.

In accordance with a broad feature of my invention, the output of the keyer-oscillator OSC, either with or without amplification, is utilized in any manner to control the transmitter-oscillator OSC', and preferably also controlling the amplifier-tubes AMP and AMP' of the carriercurrent transmitter. This keyer-control is exercised in such manner that the carrier-current transmitter is normally in a non-transmitting condition, while the keyer-oscillator OSC is oscillating. When the keyer-oscillations are blocked, the transmitter-oscillations are started, thus starting carrier-current transmission.

While any suitable keyer-control for accomplishing the broadly outlined purposes just mentioned may be utilized, in accordance with the broader aspects of my invention, I prefer to rectify the oscillation-current output of the keyeroscillator, by utilizing a transformer-secondary 36 which is coupled to the transformer-primary 33, to energize a rectifier-valve RV which is loaded by a load-resistor R3, thus producing a unidirectional-current voltage-drop in the load-resistor R3. This unidirectional voltage may be utilized in any suitable way in the control oi the carriercurrent transmitter which comprises the transmitter-oscillator OSC and the amplifiers AMP and AMP.

I prefer to utilize this unidirectional voltage, which is produced across the terminals of the load-resistor R3, as a grid-biasing voltage for applying a blocking potential to the grids of all three oi the carrier-current transmitter-tubes OSC', AMP and AMP'. This grid-biasing circuit may be traced from the negative bus through the load-resistor R3 to a conductor 31. This conductor 3i is connected, through a radio-frequency impedance RFZ, to the grid-terminal 38 of the oscillator-tube OSC' of the carrier-current transmitter. The grid-biasing conductor 31 is also connected to the mid-point of two voltage-dividing resistors Rd and R5 which are connected to the grid-terminals 39 and 39' of the amplifiertubes AMP and AMP'.

The cathode-lead el of the transmitter-oscillator OSC is directly connected to the negative bus as shown. The cathode-leads l2 of the amplifier tubes AMP and AMP' are connected through a resistor R5 to the negative bus Thus, when the keyer-oscillator OSC is oscillating, its rectied output produces a negative controlling-voltage in the load-resistor R3, which makes the grid-biasing conductor 3i suiiiciently negative, with respect to the cathodes of the transmitter-tubes OSC', AMP and AMP', so as to block operation of all three of these tubes.

The rest oi the connections of the carrier-current transmitter, are, or may be, more or less conventional. The plate-circuit d3 of the transmitter-oscillator OSC is energized, through a radio-frequency choke RFC', from the positive bus and it is also connected, through a blocking-capacitor B02, to a point All in a tuned circuit which may be traced, from the point 44, through a capacitor C3, a conductor 45, a capacitor Cri, a conductor 6 which is connected to the negative bus a capacitor C5, the grid-terminal 38 of the oscillator OSC', and a variometer V, the other terminal of which is connected to the starting point ill oi the tuned circuit. The grid-terminal 3S is also connected to the negative bus through a grid leak GL'.

The two capacitors C4 and C5 are utilized as voltage-dividing capacitors for applying the oscillatory voltage of the transmitter-oscillator OSC', through blocking-capacitors BCB and RC4, to the grid-terminals 39 and 39' of the amplifiertubes AMP and AMP. The anode-circuits Q9 and 49 of the amplier-tubes AMP and AMP' are connected to the terminals of a couplingtransformer primary 50, the mid-point 5I of which is connected to the positive terminal and also, through a blocking-capacitor B05, to the cathode-terminal d2 of the two ampliertubes AMP and AMP'. The coupling-transformer primary 5B is coupled to a secondary winding 52, one terminal oi which is grounded, and a tappoint 53 of which is connected, through a variometer V and a coupling-capacitor C6, to one of the phase-conductors of the protected line-section 3, in a well-known manner.

The coupling-transformer secondary 52 is also provided with a tapped-ofi portion 54 which is connected to a receiver-coupling transformer 55, in shunt with a voltage-limiting glow-tube 56. The receiver-coupling transformer 55 is provided with a tuned circuit including a variable capacitor Cl, and it is connected between the negative bus and the grid-terminal 5l of a receivertube REC of the carrier-current receiver. The cathode-lead 58 of this receiver-tube is connected `to an intermediate potential of a direct-currentenergized potentiometer 5G, While its anode-lead 6U is connected to the positive bus through the receiver-relay holding-coil RRH and through the telemetering relays which are marked TM relays.

The operation of the apparatus shown in Fig. 1 has been fairly well indicated during the progress of its description. In summary, attention may be called to the fact that the transmitter-oscillator OSC' is normally in a non-transmitting condition, that is, when there is no fault on the transmission system' and when no telemetering signals are being transmitted. When the telemetering key TM is operating, it rapidly opens and closes its contact, producing a brief period of carrier-current transmission whenever said telemetering key TM closes. This is accomplished by blocking the normally maintained oscillations of the keyer-oscillator OSC, and thus discontinuing the application of a blocking potential to the grid-blocking conductor 3l, thus permitting the grids of the three transmitter-tubes OSC', AMP and AMP to function.

In the form of my invention which is illustrated in Fig. l, the ripples in the rectied-current voltage of the load-resistor R3 are more or less completely filtered out by means of any suitable iiltering-means, which is illustrated in the form of a lter-capacitor FC which is connected across the terminals of the load-resistor R3. If the ripples of the unidirectional controlling-voltage of the resistor R3 are completely filtered out, the frequency of the oscillations of the keyer-oscillator OSC is immaterial. I prefer, however, to utilize a keyer-oscillator OSC which is tuned to a frequency which is higher than the carrier-current frequency of the transmitter-oscillator OSC', the keyer-frequency being something like two or three times the carrier-current frequency, so that the ripple in the rectiiied output of the keyer will not modulate the carrier-current energy.

In connection with the protective-relay control over the carrier-current transmission, as shown in Fig. i, it may be noted that the protective-relay control takes precedence over the telemetering control which is exercised by the telemetering key TM, so that, in the event or" a line-fault, the linecondition-responsive relays take complete control over whether the carrier-current transmitter does or does not transmit carrier-current energy, thus rendering the telemetering key TM inoperative 7 until the fault has been cleared from the transmission system.

There are many variations of the manner in which the general principles of my invention may be applied. In Fig. 2, I have shown a modified form oi arrangement in which the carrier-current control may be eiiected. Thus, instead of utilizing the equipment which is shown below the dotted line 'II- II in Fig. 1, I may utilize the equipment which is shown in Fig. 2,

Referring to Fig. 2, it will be noted that the four fault-responsive carrier-starting contacts Z3A, Z3B, ZSC and IOS are all connected in parallel, between the negative bus and the point 29 which corresponds to the point 29 in Fig. l. In the grid-control of the keyer-oscillator OSC, as shown in Fig. 2, the telemetering key TM is utilized alone, without the auXiiiary key-controlling relay CSK oi Fig. 1. Otherwise, the keyer-oscillator circuits of Fig. 2 are similar to those which are shown in Fig, l.

In Fig. 2, the rectified output of the keyer-oscillator, instead of being applied t a single gridbiasing circuit 3l, through a single load-resistor` R3, is applied to two separate grid-controlling circuits 3'6' and 3l, through two separate load-resisters R3 and R3, which are energized through two rectifier-valves RVS, RVZ, respectively. The ripples oi the rectied voltages may be smoothed down, as before, by means of filter-capacitors FC and FC, respectively. In Fig. 2, the grid-biasing conductor 3l' is applied solely to the grids of the transmitter-amplifiers AMP and AMP through the voltage-dividing resistors R4 and R5, While the grid-biasing conductor 3l is connected, through a radio-frequency choke RFC", to the grid-terminal 38 of the transmitter-oscillator OSC.

In Fig. 2, the fault-responsive carrier-stopping contacts, which are the back-contacts of the auxiliary relays CSP and CSG, are utilized in series With the cathode-circuit M of the transmitteroscillator OSC', and ground-preference is obtained by utilizing an extra contact 6l on the sensitive ground-fault detector 103, which is shunted around the CSP back-contact.

In Fig. 2, the receiver-relay operating-coil RR, instead of being shunted around the back-contacts of the relays CSP and CSG, is energized in the separate circuit of its own, as shown at the bottom of Fig. 2, under the control of two parallel-connected make-contacts of the relays CSP and CSG.

Otherwise, the connections in Fig. 2 are the same as in Fig. l, and the operation is the same, with the following differences, which may be noted. Since the fault-responsive carrier-stopping back-contacts CSP and CSG are connected in the cathode-circuit Qi of the transmitteroscillator OSC', these carrier-stopping contacts are capable of insuring a stoppage of carrier-current transmission, regardless of the condition of the keyer-oscillator OSC, and thus regardless of the positions of either the telemetering key TM or the four fault-responsive carrier-starting contacts 23A, ZSB, ZSC and IOS. Otherwise, the telemetering key TM and the fault-responsive carrier-starting contacts Z3A, ZSB, 23C and IOS control the oscillations of the keyer-oscillator OSC in the manner already described in connection with Fig. l.

While I have shown my invention in only two forms of embodiment, I wish it to be understood that the genera1 principles of the invention are vsusceptible of a wide variety of embodiment, and

I desire that Vthe appended claims shall be given the broadest construction consistent with their language.

I claim as my invention:

1. In combination, a carrier-current transmit-v itng-means, a contact-making transmission-controlling device, an electronic keyer including an oscillator keyer-tube so connected as to produce a substantially `iiXed-frequency oscillatory output when it is in an operative condition, the frequency of the keyer being higher than that of the carriercurrent transmitting-means, means for using the Contact-making transmission-controlling device in a control-circuit of the keyer-tube in such manner as to cause the output of the keyer-tube to be either substantially zero or substantially full-power, according to the position of the contact-making transmission-controlling device, rectiier-means for deriving a continuous sustained unidirectional voltage from the oscillatory output-energy of the keyer-tube during fullpower output-conditions of said keyer-tube, and means for using said continuous sustained unidirectional Voltage, or a lack of said continuous sustained unidirectional Voltage, to cause the carrier-current transmitting-means to have either a transmitting condition or a non-transmitting condition, or vice versa.

2. In combination, a normally non-transmitting carrier-current transmitting-means including an oscillator transmitter-tube, a normally open contact-making transmission-controlling device, an electronic keyer including a normally operative oscillator keyer-tube so connected as to produce a substantially nrqed-frequency fullpower oscillatory output, the frequency of the keyer being higher than that of the carrier-current transmitting-means, means for using the contact-making transmission-contro-lling device in a circuit of the keyer-tube in such manner as to block the oscillations of the keyer-tube when the contact of the transmission-controlling device is closed, rectier-means for deriving a continuous sustained unidirectional controllingvoltage from the oscillatory output-energy of the keyer-tube during full-power output-conditions of said keyer-tube, and means for applying said continuous sustained unidirectional controllingvoltage to a control-circuit of the oscillator transmitter-tube in such manner as to block the oscillations of said oscillator transmitter-tube when said controlling-voltage is available.

3. In combination, a carrier-current transmitting-means, an electronic keyer including an oscillator keyer-tube so connected as to produce a substantially Xed-irequency oscillatory output when it is in an operative condition, the irequency of the keyer being higher than that of the carrier-current transmitting-means, means for so controlling the keyer as to cause its oscillatory output to be either substantially zero or substantially full-power, rectifier-means for deriving a continuous sustained unidirectional voltage from the oscillatory output-energy of the keyer-tube during full-power output-conditions of said keyer-tube, and means for using said continuous sustained unidirectional voltage, or a lack of said continuous sustained undirectional voltage, to cause the carrier-current transmitting-means to have either a transmitting condition or a nontransmitting condition, or vice versa.

4. In combination, a normally non-transmitting carrier-current transmitting-means including an oscillator transmitter-tube, an electronic keyer including a normally operative oscillator keyer-tube so connected as to produce a Substantially fixed-frequency full-power oscillatory output, the frequency of the keyer being higher than that of the carrier-current transmitting-means, means for at times interrupting the operation of the oscillator keyer-tube, rectifier-means for deriving a continuous sustained unidirectional controlling-voltage from the oscillatory outputenergy of the keyer-tube during full-power output-conditions of said keyer-tube, and means for applying said continuous sustained unidirectional controlling-voltage to a control-circuit of the oscillator transmitter-tube in such manner as to block the oscillations of said oscillator trans- "militer-tube when said controlling-voltage is available.

HERBERT W. LENSNER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,588,581 Ingram et al June 15, 1926 1,728,816 White Sept. 17, 1929 Number Number 10 Name Date Price July 15, 1930 Davis Mar. 15, 1932 Vesconte et al June 18, 1935 Harder Jan. 17, 1939 Lenehan Jan. 17, 1939 Reagan Jan. 17, 1939 Kotowski et al, Nov. 28, 1939 Cramer Apr. 30, 1940 Lenehan Aug. 6, 1940 Hepp May 18, 1943 Blackburn Jan. 23, 1945 Goldsborough Mar. 20, 1945 Lensner Aug. 27, 1946 Lensner Aug. 27, 1946 Goldsborough et al. Nov. 18, 1947 FOREIGN PATENTS Country Date Germany Nov. 13, 1929 Great Britain May 3, 1943 OTHER REFERENCES Radio Engineers Handbook by Terman, 1st 25 ed. 1943, published by McGraw-Hill Book Co.,

New York city. Pages 629, 632. 

